Faster IC stubs by specializing them for Binary Smi operations

runtime/vm/object_test.cc

Index: runtime/vm/object_test.cc
===================================================================
--- runtime/vm/object_test.cc	(revision 39456)
+++ runtime/vm/object_test.cc	(working copy)
@@ -2934,7 +2934,7 @@
   Function& function = Function::Handle(GetDummyTarget("Bern"));
   const intptr_t id = 12;
   const intptr_t num_args_tested = 1;
-  const String& target_name = String::Handle(String::New("Thun"));
+  const String& target_name = String::Handle(Symbols::New("Thun"));
   const Array& args_descriptor =
       Array::Handle(ArgumentsDescriptor::New(1, Object::null_array()));
   ICData& o1 = ICData::Handle();
@@ -2949,6 +2949,7 @@
   const Function& target1 = Function::Handle(GetDummyTarget("Thun"));
   o1.AddReceiverCheck(kSmiCid, target1);
   EXPECT_EQ(1, o1.NumberOfChecks());
+  EXPECT_EQ(1, o1.NumberOfUsedChecks());
   intptr_t test_class_id = -1;
   Function& test_target = Function::Handle();
   o1.GetOneClassCheckAt(0, &test_class_id, &test_target);
@@ -2964,11 +2965,17 @@
   const Function& target2 = Function::Handle(GetDummyTarget("Thun"));
   o1.AddReceiverCheck(kDoubleCid, target2);
   EXPECT_EQ(2, o1.NumberOfChecks());
+  EXPECT_EQ(2, o1.NumberOfUsedChecks());
   o1.GetOneClassCheckAt(1, &test_class_id, &test_target);
   EXPECT_EQ(kDoubleCid, test_class_id);
   EXPECT_EQ(target2.raw(), test_target.raw());
   EXPECT_EQ(kDoubleCid, o1.GetCidAt(1));
 
+  o1.AddReceiverCheck(kMintCid, target2);
+  EXPECT_EQ(3, o1.NumberOfUsedChecks());
+  o1.SetCountAt(o1.NumberOfChecks() - 1, 0);
+  EXPECT_EQ(2, o1.NumberOfUsedChecks());
+
   ICData& o2 = ICData::Handle();
   o2 = ICData::New(function, target_name, args_descriptor, 57, 2);
   EXPECT_EQ(2, o2.NumArgsTested());